A conventional light emitting module is disclosed in PTL 1. This light emitting module includes an element substrate having a rectangular shape and a plurality of LEDs (light emitting elements) are mounted in alignment in a predetermined interval in the longitudinal direction on the element substrate. Coupling portions are provided on corner portions on both ends in the longitudinal direction of the element substrate.
A plurality of light emitting modules are arranged side by side in an annular shape with their longitudinal directions constituting the circumferential direction in a plan view, in a housing which has a cylindrical shape and is attached on a ceiling surface in a living space. At this time, the light emitting modules adjacent to each other are coupled by the coupling portions. Further, one light emitting module is connected to a power source. Thus, a lighting system installed on a ceiling surface is configured.
When power is supplied to one light emitting module, the power is supplied also to other light emitting modules via the coupling portions, emitting light from the LEDs of each of the light emitting modules. Accordingly, light distribution in a substantially circular shape can be obtained to be able to illuminate a living space.